Relative Motility of Fishes in a Southeastern Reservoir Based on Tissue Polychlorinated Biphenyl Residues

Abstract

Our objective was to investigate the potential utility of polychlorinated biphenyl (PCB) residues in fish tissue as an indicator of the relative motility of fish species in Lake Logan Martin, a 6,179-ha reservoir located in east-central Alabama. Choccolocco Creek, a midlake tributary, was the site of deposition of PCBs and this embayment had the highest concentrations of PCBs. The relationship between PCB concentrations in fish muscle tissue and the distance of the fish, at capture, from the Choccolocco Creek embayment was used to infer the relative motility of 12 species of warmwater sport and commercial fishes. Regression analyses of PCB concentration versus distance suggested that species ranged from low motility (highly significant regression and relatively high R ²) to high motility (insignificant regression or relatively low R ²). Centrarchids were relatively immotile, moronids were relatively motile, and flathead catfish Pylodictis olivaris exhibited the most motility. Our results reflect long-term (perhaps lifetime) movements of fishes in one reservoir and provide motility information on spotted bass Micropterus punctulatus, blue catfish Ictalurus furcatus, freshwater drum Aplodinotus grunniens, and white bass Morone chrysops, for which little such information has been reported. Where PCBs occur in relatively discrete areas of aquatic ecosystems, this method can provide a long-term perspective on the movements of numerous fish species under similar environmental conditions.